To get a maximum current in an external resistance of `8Omega` one can use m rows of n cells (connected in series), connected in parallel. If the total number of cells is 64 each having an e.m.f. of 2V and interanl resistance of `2Omega` , then calculate the number of cells in each row and number of rows.

Options

A. 8
B. 16
C. 4
D. 2

Answer

(A)

Explanation

From graph `e = sqrt(h/H) = sqrt(40/90) = 2/3`
Kinetic energy of the ball just after second bounce
`=1/2m(e^(2)u)^(2) = 1/2me^(4)u^(2) = e^(4)(mgH) = (2/3^(4))(2)(10)(81) = 320J`